1. Field of the Invention
The present invention relates to an illumination magnifying glass arrangement having a magnifying glass body including a cylindrical portion and a convexly curved lens section disposed on top of the cylindrical portion. Both the cylindrical portion and the curved lens section are rotationally symmetrical with respect to the cylindrical axis of the cylindrical portion.
2. Background of the Invention
In connection with a known magnifying glass arrangement of this type (German Patent DE-PS No. 35 20 293), which is particularly suitable for use in connection with digitizing tablets, a coil for the generation or detection of a magnetic field is disposed in the outer circumferential area of the cylindrical portion. The coil is placed in such a way that it is located in the area between the circumferential surface of the cylindrical portion and the path of edge light beams passing through the edge of the lens section and the cylindrical portion. Therefore, the coil is not visible to the viewer when looking through the body of the magnifying glass at the data on the digitizer. This is because the beam of light falling vertically with respect to the data on the outer edge of the lens section is deflected inwardly by the lens section in the direction of the cylindrical axis in such a way that, between it and the outer circumferential surface of the cylindrical portion, an area remains which is unrecognizable to the viewer because of the optical course of the edge light beam. For this reason, a coil located in this area is not visible and the viewer only has the impression that this part of the lens section is "opaque".
When using magnifying glasses it is often desired to further illuminate the area to be viewed. For this purpose, normally either a light source is provided above the magnifying glass body, the light from which falls through the magnifying lens body itself onto the surface to be viewed, or the surface to be viewed is illuminated from below. In the first case it is difficult to avoid dazzling light reflections, and often the light reaching the magnifying glass body is partially shielded by the viewer. Normally, illumination from below entails great constructive efforts and can, of course, only be provided in cases where the documents to be viewed are transparent.